Nope. That is not the issue.
In UK, media is struggling to raise enough revenue from either ads or subscriptions. Many MSM titles have introduced a paywall where users are forced to fund the service by either commiting to a subscription or turning off ad-bkockers and seeing ads. In contrast, Guardian's 'unique selling point' was that it would 'never' do this which was why people should prefer it to other news sources. Then, without acknowledging what it was doing, Guardian quietly introduced the same paywall as everyone it had criticised. My complaint is not about funding a service but about the hypocrisy of a service saying 'I would never do that' and then quietly doing it.
Moreover, this change is not consistent - you do not always see this paywall when visiting the Guardian. This paywall seems to be in 'trial' stage where Guardian is testing to see how much push-back they get from users. We either push-back or Guardian goes same way as rest of British MSM. That would be an irreversible loss. I think what Guardian is doing is not help its own survival long-term.
I see no difference between Guardian strategy and changes in other media (YouTube or Netflix, for example), where the owners are struggling to generate as much revenue as they expect (as they used to do). Instead of asking why their content is not popular, or why users are leaving/using ways to by-pass ads or subscriptions, they just try to squeeze out as much revenue as they can from those still willing to pay subs or see ads, while their once reliable 'goose who lays golden eggs' slowly stops laying. I say Guardian deserves to die if it does not keep track of what readers want and it is only ensuring its own death by trying to cash in on the remaining goodwill of a dwindling readership instead of attracting readers back or reaching out to new readers.
They are going up a cul-de-sac and it has no good end for Guardian. I cannot save them from themselves so I just have to find alternatives which are better at this than the parts of the industry that are dying out.
Ublock Origin does not work on my main browser Librewolf (based on Firefox, runs on linux) - its currently disabled (last time I checked was last week) as are all ad-blockers on Mozilla add-ons page. On android stuff I use Vivaldi browser (based on chromium?). I add vpn, use dns redirects, and similar stuff to anonymise/block ads and trackers. Usually stops this kinda thing but occasionally something gets through like this Guardian pop-up.